Fractionated stereotactic radiosurgery for patients with brain metastases

Stereotactic radiosurgery (SRS) delivered in 2-5 fractions (multi-fraction SRS) has been employed in patients with brain metastases as an alternative to single-fraction SRS with the aim to reduce late radiation-induced toxicity while maintaining high local control rate. In the present study we have evaluated the efficacy and toxicity of multi-fraction SRS in patients with 1-3 brain metastases. Between March 2006 and October 2012, 135 patients (63 men and 72 women) with 171 brain metastases have been treated with multi-fraction SRS (3 x 9 Gy or 3 x 12 Gy). At a median follow-up of 11.4 months, 16 lesions recurred locally. The 1- and 2-year local control rates were 88 and 72 %, respectively. The 1- and 2-year survival rates were 57 and 25 %, and respective distant failure rates were 52 and 73 %. Seventy-eight percent of patients succumbed to their extracranial disease and 22 % died of progressive intracranial disease. Multivariate analysis showed that melanoma histology was predictive of local failure (p = 0.02; HR 6.1, 95 % CI 1.5-24). Specifically, the 1-year local control rates were 68 % for melanoma, 92 % for breast carcinoma, and 88 % for NSCLC, respectively. Stable extracranial disease (p = 0.004) and Karnofsky performance status (p = 0.01) were predictive of longer survival. Radiologic changes suggestive of radionecrosis occurred in 12 (7 %) out of 171 lesions, with an actuarial risk of 9 % at 1 year and 17 % at 2 years, respectively. In conclusion, multi-fraction SRS appears to be an effective and safe treatment modality for brain metastases. It may represent an alternative to single-dose SRS for patients with large lesions or lesions located near critical structures.